Hydraulic draft gear arrangement



A TT'YS Oct. 1, 1968 w. H. PETERSON HYDRAULIC DRAFT GEAR ARRANGEMENT 6Sheets-Sheet 1 Original Filed March 15. 1965 INVENTOR WILLIAM H.PETERSON W H- PETERSON 6 Sheets-Sheet 2 nvvewron WILLIAM H. PETERSON w WW ATT'YS Oct. 1, 1968 HYDRAULIC DRAFT GEAR ARRANGEMENT Original FiledMarch 15. 1965 Oct. 1, 1968 w. H PETERSON HYDRAULIC DRAFT GEARARRANGEMENT 6 Sheets-Sheet 4 Original Filed March 15. 1965 d/Zm 4/ 8 MN.v To T MS. T m% W E% P H W M L "2 W B Oct. 1, 1968 w. H. PETERSONHYDRAULIC DRAFT GEAR ARRANGEMENT e Sheets-Sheet e I Original Filed March15, 1965 FT Q15.

lilll iiiii INVENTOR WILLIAM H. PETERSON United States Patent OfficeReissued Oct. 1, 1968 26,472 HYDRAULIC DRAFT GEAR ARRANGEMENT William H.Peterson, I-Iomewood, 11]., assignor to Pullman Incorporated, Chicago,III., a corporation of Delaware Original No. 3,275,164, dated Sept. 27,1966, Ser. No.

533,751, Feb. 2, 1966, which is a continuation of Ser.

No. 439,630, Mar. 15, 1965. Application for reissue Dec. 9, 1966, Ser.No. 607,348

12 Claims. (Cl. 213-43) Matter enclosed in heavy brackets appears in theoriginal patent but forms no part of this reissue specification; matterprinted in italics indicates the additions made by reissue.

ABSTRACT OF THE DISCLOSURE A double acting hydraulic cushion deviceformed with a hydraulic filled cylinder and lengthwise spaced endplates. A piston assembly is disposed for relative reciprocation withinsaid cylinder including a piston head and a piston rod extending fromone face thereof through one of the end plate means. A flexibleaccumulator in the form of an expandible boot is fixed at one end to theend of the piston rod extending outwardly from the cylinder and at theother end to the end plate means. The device is provided with a meteringmeans for controlling the flow of fluid from one side of the piston headto the other. Disposed in a bore extending from the piston head to theaccumulator chamber is a pressure relief valve. A fluid pressure forceresponsive valve means is movably disposed in a chamber contiguous withthe accumulator chamber for movement to a position overlying openingsproviding communication from the cylinder to the accumulator boot and aposition clear of the openings to permit free fluid pasage.

This is a continuation of United States patent application Serial No.439,630, filed March 15, 1965.

My invention relates to a hydraulic draft gear arrangement for railroadcars, and more particularly, to a hydraulic draft gear arrangementproviding cushioning for both buff and draft impacts during operation ofa railroad car to which the arrangement is applied.

A significant problem in the hydraulic draft gear art lies in the factthat occasionally coupler impact situations will be encountered whichwill generate forces within the gear that can exceed the design strengthof the gear. These situations may be caused by impacts at excessivespeeds or impacts against a substantially fixed mass of excessiveweight, such as a cut of three or more cars with their brakes set, or acombination of these factors.

A principal object of this invention is to provide a hydraulic draftgear arrangement that provides for an improved pressure relief valvearrangement which is incorporated within the confines of the gear pistonhead and rod, for relieving the pressures generated within the gear whenextreme impact situations are encountered.

Another principal object of the invention is to provide a generallyimproved hydraulic cushioning device that is adaptable for both end ofcar and center of car cushioning arrangements.

Other objects of the invention are to provide a one piece piston headand rod arrangement that reduces machining of these parts to a minimumand eliminates the need for welding and its consequent distortions; to

provide a hydraulic cushion arrangement that is especially adapted tohandle overload situations, and to provide a hydraulic cushioningarrangement that is inexpensive of manufacture, convenient to install,and efficient in operation.

Other objects, uses, and advantages will be obvious or become apparentfrom a consideration of the following detailed description and theapplication drawings.

In the drawings:

FIGURE 1 is a fragmental longitudinal horizontal sectional view takenthrough the draft sill of a railroad car, showing in plan one embodimentof the present invention, parts being broken away to expose other parts,and showing the draft gear in the position it assumes at the end of a.butt impact on the coupler;

FIGURE 2 is a fragmental vertical sectional view through the draft sillof FIGURE 1, showing in elevation the draft gear in the position itassumes under the impact situation of FIGURE 1;

FIGURE 3 is a diagrammatic perspective view in section of the hydrauliccushioning unit that forms a part of the draft gear arrangement ofFIGURES l and 2, parts being omitted to better illustrate other parts;

FIGURE 4 is a longitudinal sectional view through the hydrauliccushioning unit, with the full line showing of the piston indicating thelocation of the piston in draft, and the broken line showing of thepiston indicating the location of the piston at the end of its buffstroke;

FIGURE 5 is a fragmental large scale sectional view illustrating aportion of the piston pressure relief valve that is shown in FIGURE 4;

FIGURE 6 is a cross-sectional view substantially along line 66 of FIGURE4;

FIGURE 7 is a cross-sectional view substantially along line 7--7 ofFIGURE 4;

FIGURE 8 is a cross-sectional view substantially along line 8-8 ofFIGURE 2;

FIGURE 9 is a cross-sectional view substantially along line 99 of FIGURE2;

FIGURE 10 is a plan view of the rear end plate of the hydrauliccushioning device, with the cover plates that are indicated in FIGURE 3being omitted;

FIGURE 11 is a cross-sectional view substantially along line 11-41 ofFIGURE 10;

FIGURE 12 is a plan view of the forward end plate of the hydrauliccushioning device, showing the rear side thereof;

FIGURE 13 is a fragmental cross-sectional view substantially along line1313 of FIGURE 12; and

FIGURE 14 is a plan view of the from base plate of the hydrauliccushioning device, showing the rearward face thereof.

However, it is to be understood that the drawing illustrations aresupplied primarily to comply with the requirements of 35 U.S.C. 112, andthat the invention is susceptible of other embodiments that come withinthe scope of the appended claims.

GENERAL DESCRIPTION Referring first to FIGS. 1 and 2 of the drawings,refcrence numeral 10 generally indicates a conventional railroad cardraft sill, which may comprise the end portion of the car bodystationary or fixed center sill, or comprise a separate constructionthat is welded to the ends of such center sill, as is well known in theart.

The draft 10, which is shown in the drawings as comprising a pair ofvertically disposed spaced side plates 11 welded to a top cover plate12, defines a pocket 14 in which one embodiment 16 of the hydraulicdraft gear arrangement of the present invention is mounted.

The draft gear arrangement 16 comprises a hydraulic cushioning device 18(see FIGS. 3 and 4) that includes a piston member 20 defining a pistonhead 22 (see FIGS. 3 and 4) and a piston rod 24 which extends forwardlyof the draft gear pocket into yoke 26 (FIGS. 1 and 2) where it isconnected to follower plate 30 by a suitable screw threaded or othertype of fixed connection.

The hydraulic cushioning device 18 further comprises a housing 32 inwhich is mounted a cylinder 34 (see FIGS. 4 and 5) in which the pistonhead 22 operates, with the housing 32 being applied in the draft gearpocket 14 between pairs of opposed lugs or stops 36 and 38 that areaffixed to the draft sill 10, as by welding.

The yoke 26 is of a familiar type that defines a bight portion 40 inwhich is mounted a rubber pad type cushioning device 42 that isinterposed between the rear 44 of the yoke bight portion and thefollower plate 30. The follower plate 30 is proportioned laterally ofthe draft sill 10 to engage lugs or stops 46 [and] in the draft positionof the draft gear arrangement 16.

The shank 48 of a coupler 50 is pivotally secured between the arms 52 ofthe yoke by a suitable coupler pin 54.

A compression spring 56 acting between a spring seat 58 that is fixedwith respect to the draft sill and a spring seat 60 that is fixed withrespect to yoke 26 maintains the draft gear arrangement in its draftposition with follower 30 hearing against lugs 46.

Draft forces acting on coupler 50 when the car is at a standstill arecushioned by the resilient pad cushioning device 42 while buff impactforces are cushioned by the hydraulic cushion device 18 through thepiston member 20 moving from the full line position of FIG. 4 to thebroken position of the same figure and forcing hydraulic liquid throughorifices in dash pot like fashion, with the hydraulic cushioning devicebeing arranged to offer a substantially constant resistance in absorbingthe buff impact. After the buff impact is absorbed, spring device 56returns the hydraulic cushioning unit to the draft position.

During running train operations there may be conditions in "which adraft impact is imposed on the coupler immediately following a buffimpact and prior to the return of the piston rod member 20 to the fullline position of FIG. 4. Under such conditions of draft impact thehydraulic liquid is again forced through the orifices and the cushioningdevice offers a substantially constant resistance. Should the energy ofthe draft impact not be absorbed when the piston member returns to thefull line position, the resilient pad cushioning device 42 may providefurther cushioning.

Associated with the hydraulic cushioning unit 18 is a novel pressurerelief valve device 62 (see FIGS. 3 and 4), which protects the hydrauliccushioning device against overload conditions caused by impacts atexcessive speeds, or the like.

SPECIFIC DESCRIPTION The specific features of hydraulic cushioningdevice 18 and its pressure relief valve 62 are shown in FIGS. 38 and10-14.

The hydraulic cushioning device housing 32 comprises a shell or casingof generally quadrilateral transverse cross-sectional configuration (seeFIGS. 6 and 7), which may be defined by a pair of channel shaped members72 welded together as at 74. Associated with the casing or shell 70 areforward and rearward end plates 76 and 77, which also mount between themcylinder 34 in which piston member 20 operates.

As indicated in FIG. 4, the end plates 76 and 77 are each formed wihrecesses indicated at 78 and 80, respectively, in which the ends 82 and84 of the cylinder 34 are respectively received. The end plates 76 and77 are also recessed as at 86 and 88, respectively, to receive therespective ends 90 and 92 of the shell or casing. The end plates 76 and77 are secured to the cylinder and shell or casing respectively bywelding, as indicated in FIG. 4, although any other suitable means ofsecurement that provides an effective hydraulic seal may be employed, aswill be understood by those skilled in the art.

As clearly indicated by FIGS. 3, 4, 6 and 7, the cylinder 34 defineswith the end plates 76 and 77 a working chamber 94 in which the pistonmember head 22 operates. The casing or shell 70 defines with cylinder 34and end plates 76 and 77 an annular reservoir 96 for hydraulic liquidwith which the cushioning device 18 is filled, as through a port 97 inshell or casing 70 (see FIG. 4) which may be sealed off by a suitableplug 98.

The cylinder 34 is preferably formed with a plurality of orifices 100that are arranged to provide a substantially constant force travelcharacteristic when the piston member 20 is moved under both buff anddraft impacts between the full line position of FIG 4 and the brokenline position of that figure. This may be done in any conventionalmanner, as by making orifices 100 all of the same diameter and spacingthem at the varying distances required, or by forming the orifices 100of varying diameters and spacing them uniformly lengthwise of thecylinder all as required in accordance with known procedures in this artto achieve substantially constant force travel closure characteristics.As many orifices 100 may be provided in the cylinder 34 as may berequired for efiicient operation of cushioning device 18.

The front end plate 76 is formed to define a threaded opening 102 whichthreadedly receives an annular collar 104 through which the piston rod24 extends. Interposed between the piston rod and the collar is anon-metallic ring 106 that is preferably formed of a laminated resin,such as the type designated by the National Electrical ManufacturersAssociation as 9 coarse, grade C. Preferably the plastic ring 106 as anID. that substantially complements the OD. of the piston rod, and whichis sufficiently less than the ID. of the collar 104 at its annularopening 108 to avoid metal to metal contact between ring 106 and thepiston rod 24. Ring 106 is seated in annular recess 110 of collar 104.

The collar 104 is also formed with a plurality of ports or passages 112and an annular flange portion 114 that receives an annular flap valveplate 116 which is secured against displacement from flange portion 114by a suitable locking ring 118.

As indicated in FIGS 3 and 4, end plate 76 has secured thereto byappropriate bolts (indicated in dashed lines at 120 in FIG. 4) a baseplate 122 that defines a radially inwardly extending annular ridgeportion 124 through which piston rod 24 extends.

The base plate 122 on its rearward side defines a recess 125 that isquadrilateral in configuration and substantially complements theexterior transverse cross-sectional configuration of plate 122; recess125 receives the collar 104 when the base plate 122 is secured to theend plate 76, as indicated in FIGS. 3 and 4. As the collar 104 is roundor cylindrical in configuration, the base plate 122 recess 125 [refines]defines with the collar 104 at each of the four corners of the baseplate 122 a passage 128 which in accordance with the present arrangementis aligned with a correspondingly placed passage 126 formed in the endplate 76 in the manner suggested in FIG. 3. This provides for hydraulicliquid communication between the reservoir 96 and external surface 129of the piston rod 24 exteriorly of the [car] collar 104 through the fourcorners of the abutting plates 76 and 122. Hydraulic liquidcommunication is also provided for between the same portion of thepiston rod 24 and the chamber 94 through ports 112 of collar I04 andaround flap plate 116, when the flap plate 116 is not seated in checkvalve closing relation over the ends of the ports 112 (plate 116 isproportioned to do this, as indicated in FIG 4).

End plate 77 at each of its four corners is provided with a passagewhich provides hydraulic liquid communication between reservoir 96 andrecesses 132 which are formed at each corner (see FIGS. 3, 10 and 11).Each recess 132 is sealed shut by welding in place an appropriate coverelement 134, and each recess 132, which with the cover plate 134 definesa passage 136, communicates with chamber 94 through a passage 138 formedin the end plate 77.

As indicated in FIGS. 3 and 11, the passages 138 terminate in an annularrecess 140 formed in the forward face of end plate 77 in which anannular member or ring 142 is fixed, as by welding at 143. Annularmember or ring 142 has mounted therein an annular flap valve plate 144which is secured against displacement within the ring 142 by a suitablelocking ring 146. The locking ring 146 is spaced lengthwise from thering 142 so that the flap valve plate 144 is displaceable from a closedposition overlying the passage 138 to a position clear thereof againstthe ring 142.

Thus, hydraulic liquid communication is provided between reservoir 96and chamber 94 through passages 130, 136, 138, when flap valve plate 144is displaced from check valve closing relation with respect to passages138. Flap valve plate 144 [142] is proportioned to overlie the passages138, as indicated in FIG. 3.

It will thus be seen that the end plates 76, 77 and base plate 122 arequadrilateral in transverse crosssectional configuration and areprovided with hydraulic liquid conducting passageways at their fourcorners.

Secured to the annular ridge portion 124 of base plate 122 is one end150 of an annular flexible static seal member or boot accumulator 152that has its other end 154 turned outside in, with said end 154 beingsecured to the piston rod 24.

In the case of the boot end 150, this end is locked between a shoulder156 and a ring 158 held in place by a suitable locking ring 160, whilein the case of the boot end 154, it is held in place by being securedbetween a pair of annular members 162 and 164 against which abut therespective sleeves 166 and 168 that are held in place by suitablelocking rings 170 and 172, respectively. Parenthetically, all lockingrings referred to herein, such as rings 170 and 172, are seated inappropriate recesses, in accordance with standard practice in connectionwith such devices.

The annular static seal member or boot 152 thus defines with the pistonrod 24 an annular hydraulic liquid receiving chamber 174.

Base plate 122 has affixed thereto as by welding an annular extensionring or cylinder 176, which is proportioned to overlie the boot 152 whenthe hydraulic cushion device 18 is in its contracted relation (see thedashed line showing of FIG. 4).

Base plate 122 is formed with an endless recess 178 about its recess 125which receives a suitable O-ring seal 180 for insuring a hydraulicliquid seal between the base plae 122 and end plate 76 [176] (see FIG.4). This has been omitted from the showing of FIG. 3 to simplify thedrawing of that figure.

The piston member 20 in accordance with this invention is a one pieceelement formed from a suitable forging steel or the like to permit thepiston head 22 to be formed to a suitable piston head configuration byan appropriate forging operation. One suitable material .for thispurpose is C-lOSt) Steel, normalized and of a suitable forging quality.

The rim of the pisfon head is suitably machined to form annular recess192 in which a laminated plastic ring 194 is mounted. Ring 194 ispreferably made of the same substance as ring 106, and preferably has anCD. that exceeds that of piston head rim 190 sufficiently to preventmetal to metal contact beiween piston head 22 and cylinder 94.

The piston rod 24 may be appropriately threaded at its other end forreception in a threaded socket formed in the mid portion of follower 30,for securing same to the follower 30.

The pressure relief valve 62 in accordance with this invention ismounted entirely within the piston member 20. As indicated in FIGS. 3, 4and 5, the piston member 20 is formed with a longitudinally extendingbore 200 that is counterbored as at 202 to receive compression spring204 which extends into a cylindrical valve chamber 206 in which isslidably mounted an annular valve stem member 208 that preferably has anOD. that substantially complements the ID. of the chamber 206. Fixed tothe tubular valve stem member 208 are a plurality of studs or pins 210that extend longitudinally of the axis of bore 200 and chamber 206 andbear against a disc 212 that has secured thereto a pin 214 which alsoextends longitudinally of the axes of bore 200 and chamber 206. The pin214 is slidably mounted within a bore 216 formed in a retainer nut 218that is threadedly mounted at the piston head end of chamber 206.

The piston member 20 is formed with a plurality of diagonal passages 220defining inlet ports 222 at the working face or high pressure side 224of the piston head 22 and exhaust ports 226 opening into chamber 206.

The bore 200 communicates wih a plurality of cross bores 228 that extendtransversely of the piston rod 24 and terminate in exhaust ports 230which are directed laterally of the piston rod. As indicated in FIG. 4,the sleeve 166, in accordance with this inven ion. is preferably formedwith an extension 232 which overlies the ports 230 and deflectshydraulic liquid discharge from ports 230 to the left [right] of FIG. 4rather than directly against the static seal member 152.

Spring 204 is selected to have a strength such as to hold the tubularvalve stem member 208 substantially in the position shown in FIG. 5during normal operation of the gear on cushioning buff and draft forces.However, the strength is selected such that when excessive buff impactconditions cause pressures to rise in chamber 94 to about 85 to 90percent of the strength of cylinder 34, the pressure acting on the end234 of pin 214 will force stem 208, through disc 212 and pins 210, tothe right of FIG. 5 to the exent that ports 226 will be opened tochamber 206 and thus to bore 200 through the hollow center of thehelical spring 204. This permits hydraulic liquid to discharge throughthe relief valve 62 and to chamber 174, and thus relieve the excesspressures building up in cylinder 94.

The arrangement of valve 62 as illustrated and described permits the useof a spring with a relatively light preload to adequately protect thehydraulic cushion unit. For instance, spring 204 can be arranged to havea preload as light as on the order of two hundred and eighty pounds, andyet hold the valve 62 closed up to pressures on the order of twelvethousand p.s.i. in chamber 94. A suiable spring for this purpose isformed from Vanadium Steel or its equivalent into four gauge wire sizeand provided with a spring rate of [31.6 pounds per inch with twenty-sixactive coils and an outside diameter of one and one-quarter inches.

In use, the hydraulic cushioning unit 18 is fully charged with hydraulicliquid in the spaces defined by the reservoir 96, the chamber 94, thechamber 174, and all passages connecting same. This may be done in anysuitable manner, but care should be taken to have all air bled out ofthe sysetm while at the same time avoid ing overcharging of the unit.The boot 152 should be disposed substantially as shown in the full linesof FIG- URE 4 when properly charged with hydraulic liquid.

In normal buff impact absorbing operation, the piston member 20 movesfrom the full line position to the broken line position of FIG. 4, andthe valve 62 remains closed. As the piston head moves between these twopositions, hydraulic liquid discharges from chamber 94 through theorifices 100 into reservoir 96 and returns to the chamber 94 on the oherside of the piston head 22 through the orifices 100 that the piston head22 has passed, as well as through passages 126, 128, 112 and valve plate116. Flap valve plate 144 under the pressure build up before piston side224 shuts off the passages 138 in the end plate 77. This hydraulicliquid flow continues until the piston head reaches its maximum extentof buff absorhing travel (approximately the broken line position of FIG.4) during which travel there is provided a substantially constantcushioning force. If the buff impact is applied on the coupler 50 whenthe car is at a standstill, the compression spring 56 acting on yoke 26and therefore on piston rod 24 draws the piston member 20 to the rightof FIG. 4 and reverses the hydraulic liquid flow from chamber 94.

During train running or moving conditions a draft impact or force mayact on the couplers 50 when the piston member 20 is in the broken lineposition as a result of a prior buff impact. Under these conditions thehydraulic liquid flow will then be from the side 225 of piston head 22through the orifices 100 on the high pressure piston side 225 and toreservoir 96 and then back into chamber 94 through those of the orifices100 that have been opened by the movement to the right of FIG. 4 of thepiston member 20. Such flow of the hydraulic liquid will result in asubstantially constant cushioning force because of the spacing of theorifices 100. Also, flap valve plate 116 will close off passages 112 andhydraulic liquid flow will occur between reservoir 96 and chamber 94through passages 130, 136 and 138 of end plate 77 [177] and past flapvalve plate 144.

From the foregoing it should be readily apparent that the hydrauliccushioning unit 18 is double-acting by providing cushioning during bothdraft and buff impact.

One function of the accumulator or the flexible static seal 152 is toform an accumulator chamber to take the hydraulic liquid displaced fromchamber 94 by the entry of the piston rod 24 into same, and as indicatedby the broken line showing of FIG. 4, the seal member 152 expandssomewhat under the pressure of the additional hydraulic liquiddischarged into the chamber 174. The member 152 is made sufficientlyresilient so that as the piston member 20 returns to the full lineposition of FIG. 4, it tends to aid in discharging hydraulic liquid fromchamber 174 back through the passages 128 and 126 and into reservoir 96,etc. Chamber 174 also serves as a surge chamber to take care ofexcessive pressure increases in reservoir 96; pressures in reservoir 96are relieved through passages 126 and 128.

The cushioning devices 42 (FIGS. 1 and 2) comprise a plurality of rubberpads 250 which are adhered to the opposite sides of metallic separatingplates or discs 252. As indicated in FIG. 9. the piston rod 24 passesthrough the cushion device 42, and as already indicated, the cushiondevice 42 abuts against follower 30 to which the piston rod 24 issecured.

Follower plate 30 is formed on its outwardly facing surface 254 with aspherically contoured projection 256 (see FIG. 2) which seats within acomplementarily shaped concave surface or seat 258 formed in the yoke26.

The spring seat 58 is affixed in any suitable manner, as by welding, tothe bottom of the draft gear pocket bottom closure plate 259 that isfixed between the draft sill side walls 11 as indicated in FIGS. 8 and9. Plate 259 as illustrated is in the form of a channel shaped memberfixed in place by appropriate bolts 261.

Spring seat 60 is secured to the yoke by being afiixed to spaced plates260 (see FIG. 9) that operate in slots 262 formed in closure plate 259,and are themselves affixed to the yoke substantially in the mannerindicated in FIG. 9. A suitable strengthening and motion guiding web 264may be affixed between the plates 260 substantially in the mannerindicated in P16. 9.

The movement of the yoke may be guided laterally by providingappropriate guide members within the draft sill where indicated at 266in FIG. 9.

The lugs or stops 36, 38 and 46 may be of the type commonly used indraft gear pockets and comprise suitable abutments 270 aflixed inplaceas by welding and reinforced by appropriate strengthening webs 272.Different sizes and shapes of these elements for the respective lugs orstops 36, 38, and 46 are indicated in the drawings, but the functions ofthese elements are the same, as will be immediately apparent to thoseskilled in the art.

The specific draft sill structure shown in the drawings is adapted foruse in a railway car having a fioor height wherein a portion of thedraft sill is elevated above the floor. To this end, the rear end wall13 of the cover plate 12 depends downwardly to the car fioor level, asindicated in FIG. 2.

The draft gear arrangement 16 includes a number of improvements inaddition to the relief valve 62.

As already mentioned in connection with the hydraulic cushioning device,the piston member 20 is a one piece element, which eliminates the needto weld the piston head on a piston rod and the consequent distortionsdue to heat treating in welding.

Furthermore, it will be noted that the boot 152 not only serves toaccumulate the hydraulic liquid displaced from the chamber 94 by thefull entry of the piston rod into that chamber, but it also serves as asurge chamber to minimize forces within the reservoir 96 and the chamber94 during displacement of the hydraulic liquid by the piston 20.

The piston arrangement also eliminates to a considerable extent themachining that has formerly been required in connection with componentsof this type.

The relief valve is simple and reliable and does not require a sensitiveadjustment to adapt it to its desired working conditions. The reliefvalve is entirely housed within the piston member, thus is not onlycompactly arranged but fully protected during use.

Reference is hereby made to my copending application Serial No. 310,661,filed September 23, 1963, and the copending application Serial No.369,708, filed May 25, 1964, of myself and Carl Adler, the disclosuresof which are hereby incorporated herein by this reference.

The foregoing description and the drawings are given merely to explainand illustrate my invention and the invention is not to be limitedthereto, except insofar as the appended claims are so limited, sincethose skilled in the art who have my disclosure before them will be ableto make modifications and variations therein without departing from thescope of the invention.

What is claimed is:

1. A hydraulic cushioning device for draft gear or the likeand operativeto cushion buff and draft impacts comprlsmg:

a housing,

a cylinder mounted in said housing,

a piston member reciprocably mounted in said cylinder,

said piston member comprising a piston head posi tioned in said cylinderand a piston rod projecting outwardly of said cylinder,

said piston head including a high pressure generating side upon buffimpact to said cushion device,

saig piston head and rod being a one piece piston memmeans for effectinga hydraulic liquid seal between said rod and said housing,

pressure relief valve means carried by said piston member,

said relief valve means comprising:

a bore formed in said rod and extendin longitudinally thereof andinwardly of the head end thereof,

a valve member reciprocably mounted in said bore and proportioned tosubstantially complement the width of said bore,

resilient means biasing said valve member outwardly of said bore,

stop means for limiting the movement of said member outwardly of saidbore,

and an actuator member shiftably mounted in said head and having one endthereof operably engaging said valve member and the other end thereofexposed at said high pressure side of said piston head,

said resilient means being prestressed to position said valve member atpredetermined positions,

said piston head being formed with conduit means extending between saidhigh pressure side thereof and the position of said valve member when inits said predetermined position,

and accumulator means operably connected with said bore inwardly of saidrelief valve means,

said actuator member shifting said valve member against the action ofsaid resilient means to place said piston head conduit means intocommunication with said accumulator means when said piston head highpressure side is subjected to pressures above a predetermined maximum.

2. A hydraulic cushioning device for draft gear or the like andoperative to cushion buff and draft impacts, said device comprising:

a cylinder,

a piston member reciprocably mounted in said cylinder,

said piston member comprising a piston head positioned in said cylinderand a piston rod projecting outwardly of said cylinder,

said piston head including a high pressure generating side upon buffimpact to said cushion device,

means for effecting a hydraulic liquid seal between said rod and saidcylinder,

and pressure relief valve means carried by said piston member,

said relief valve means comprising:

a bore formed in said rod and extending longitudinally thereof andinwardly of the head end thereof,

a valve member reciprocably mounted in said bore and proportioned tosubstantially complement the width of said bore,

resilient means biasing said valve member outwardly of said bore,

stop means for limiting the movement of said member outwardly of saidbore,

and an actuator member shiftably mounted in said head and having one endthereof operably engaging said valve member and the other end thereofexposed at said high pressure side of said piston head,

said resilient means being prestressed to position said valve member ata predetermined position,

said piston head being formed with conduit means extending between saidhigh pressure side thereof and the position of said valve member when in"its said predetermined position,

and accumulator means operably connected with saidbore inwardly of saidrelief valve means. 3. A hydraulic cushioning device for draft gear orthe like and operative to cushion buff and draft impacts, said devicecomprising:

a housing,

a cylinder mounted in said housing,

a pistoh'member reciprocably mounted in said cylinder,

said piston member comprising a piston head positioned in said cylinderand a piston rod projecting outwardly of said cylinder,

said piston head including a high pressure generating side upon buffimpact to said cushion device,

means for effecting a hydraulic liquid seal between said rod and saidhousing,

pressure relief valve means carried by said piston memher,

said relief valve means comprising:

a bore formed in said rod and extending longitudinally thereof andinwardly of the head end thereof,

a tubular valve stem member reciprocably mounted in said bore andproportioned to substantially complement the width of said bore,

a spindle valve member mounted in said bore and actuated by said valvestem,

resilient means biasing said valve stem member outwardly of said bore,

stop means for limiting the movement of said members outwardly of saidbore,

and an actuator member shiftably mounted in said head and having one endthereof operably engaging said spindle valve member and the other endthereof exposed at said high pressure side of said piston head,

said resilient means being prestressed to position said valve stem andsaid spindle valve members at predetermined positions,

said piston head being formed with conduit means extending between saidhigh pressure side thereof and the position of said valve stem memberwhen in its said predetermined position,

and accumulator means operably connected with said bore inwardly of saidrelief valve means.

4. A hydraulic cushioning device for hydraulic draft gear or the likeand operative to cushion buff and draft impacts, comprising:

a housing,

a cylinder mounted in said housing and defining a hydraulic chamber,

a piston member reciprocably mounted in said cylinder chamber,

said piston member comprising a piston head positioned in said cylinderchamber and a piston rod projecting outwardly of one end of saidhousing,

said piston bead including a high pressure generating side upon bulfimpact to said cushion device,

said piston head and rod being a one piece piston memher, with the spacebetween said housing and said cylinder comprising a hydraulic liquidreservoir,

orifice means formed in said cylinder at points spaced axially of saidcylinder for providing communication between said space and saidcylinder chamber,

means for elfecting a hydraulic liquid seal between said rod and saidone end of said housing,

pressure relief valve means carried by said piston memher.

said relief valve means comp-rising:

a bore formed in said rod and extending longitudinally thereof andinwardly of the head end thereof,

a tubular valve stem member reciprocably mounted in said bore andproportioned to substantially complement the width of said bore,

a spindle valve member mounted in said bore and actuated by said valvestem,

resilient means biasing said valve stem member outwardly of said bore,

stop means for limiting the movement of said members outwardly of saidbore,

and an actuator member shiftably mounted in said head and having one endthereof operably engaging said spindle valve member and the other endthereof exposed at said high pressure side of said piston head,

said resilient means 'being prestressed to position 1 1 said valve stemand said spindle valve members at predetermined position, said pistonhead being formed with conduit means extending between said highpressure side thereof and the position of said valve stem member when inits said predetermined position, and accumulator means operablyconnected with said bore inwardly of relief valve means. 5 The deviceset forth in claim 4 wherein said housing includes an end platestructure at each end of said cylinder forming the ends of saidcylinder, said end plate structure of said one end of said housing beingformed to define conduit means communicat: ing with said reservoir, andmeans for defining an annular hydraulic liquid accumulator chamber aboutsaid piston rod exteriorly of said housing, said accumulator chambercomprising said accumulator means, said conduit means communicating withsaid chamber. 6. The device set forth in claim 5 wherein said end platestructure at said housing one end includes a collar portion proportionedto receive said piston rod,

and dynamic seal means interposed between said collar and said rod, saidcollar portion 'being formed to define conduit means communicatingbetween said accumulator chamber and said cylinder chamber, and checkvalve means operably connected with said collar portion conduit meansfor blocking hydraulic liquid flow therethrough toward said accumulatorchamber. 7. The device set forth in claim 6 wherein:

said accumulator chamber defining means comprises a resiliently flexibleannular member having one end thereof secured to said housing one endand the other end thereof secured to said piston rod, said flexibleannular member comprising said hydraulic liquid seal effecting means. 8.The device set forth in claim 5 wherein: said end plate structure at theother end of said housing includes conduit means communicating betweensaid reservoir and said cylinder chamber and check valve means operablyconnected therewith for blocking hydraulic liquid flow from saidcylinder chamber to said reservoir. 9. A draft gear arrangement forrailway cars, said arrangement comprising:

a hydraulic cushioning device, said device comprising:

a housing, a cylinder mounted in said housing and defining a hydraulicchamber, a piston member reciprocably mounted in said cylinder chamber,said piston member comprising a piston head positioned in said cylinderchamber and a piston rod projecting outwardly of one end of saidhousing, said piston head including a high pressure generating side uponbud impact to said cushion device, said piston head and rod being a onepiece piston member, with the space between said housing and saidcylinder comprising a hydraulic liquid reservoir, orifice means formedin said cylinder at points spaced axially of said cylinder for providingcommunication between said space and said cylinder chamber, means foreffecting a hydraulic liquid seal between said rod and said one end ofsaid housing, pressure relief valve means carried by said piston member.said relief valve means comprising:

12 a bore formed in said rod and extending longitudinally thereof andinwardly of the head end thereof,

a valve member reciprocably mounted in said bore and proportioned tosubstantially complement the width of said bore,

resilient means biasing said valve member outwardly of said bore,

stop means for limiting the movement of said valve member outwardly ofsaid bore,

and an actuator member shiftably mounted in said head and having one endthereof operably engaging said valve member and the other end thereofexposed at said high pressure side of said piston head,

said resilient means being prestressed to position said valve member apredetermined position,

said piston head being formed with conduit means extending between saidhigh pressure side thereof and the position of said valve stem memberwhen in its said predetermined position,

and accumulator means operably connected with said bore inwardly of saidrelief valve means,

said housing being fixed with respect to the car,

said rod being connected to a yoke member,

said yoke member being mounted for movement longitudinally of the carbetween a buff limit position inwardly of the car and a draft limitposition outwardly of the car,

said draft limit position being defined by stop means fixed with respectto the car,

and resilient cushioning means carried by said yoke and interposedbetween the last mentioned stop means and said yoke.

10. The device set forth in claim 3 in which the housing includes firstand second end plate means at opposite ends of the cylinder,

the piston head divides the cylinder into a first chamber and a secondchamber,

said second chamber contains the piston rod,

the piston rod is connected at one end to the piston head and extendsthrough said first end plate means, the accumulator means is resilientand is fixed between the first end plate means and the piston rod forreceiving hydraulic fluid displaced by the piston head during travel ofthe head and rod in the cylinder,

the pressure relief valve means is yieldable to pressure force in saidfirst chamber to permit hydraulic fluid flow through the bore into theaccumulator means,

the cylinder includes hydraulic fluid metering means for controlling theflow of hydraulic fluid between said two chambers in both directions oftravel of the piston head so as to impart predetermined cushioncharacteristics to the device,

means is provided establishing communication between said first chamberand said accumulator means including said metering means and an openingin said first end plate means,

and valve means is movably disposed in said second chamber forinteraction with said opening so as to be responsive to diflercntialfluid forces acting on said valve means to move said valve means to aposition restricting hydraulic fluid flow through said opening when thepiston head moves toward said first end plate means,

and to a position permitting free flow from said accumulator meansthrough said opening when said piston head moves in the oppositedirection.

11. A hydraulic cushioning device for draft gear or the like andoperative to cushion bufi and draft impacts, said device comprising ahousing providing a hydraulic fluid filled cylinder having first (milsecond and plate moans at opposite ends of I/u' cylindcr,

a piston head dividing the cylinder into a first chamber and a secondchamber,

a piston rod in said second chamber connected at one end to the pistonhead, extending through said first end plate means and having alongitudinal bore therein,

resilient accumulator means fixed between the first end plate means andthe piston rod for receiving hydraulic fluid displaced by the pistonhead and rod during travel of the head and rod in the cylinder,

pressure relief valve means carried by the piston head and yieldable topressure force in said first chamber to permit hydraulic fluid flowthrough the bore into the accumulator means,

said cylinder including hydraulic fluid metering means for controllingthe flow of hydraulic fluid between the two chambers in both directionsof travel of the piston head so as to impart predetermined cushioncharacteristics to the device,

means establishing communication between said first chamber and saidaccumulator means inluding said metering means and an opening in saidfirst end plate means,

and valve means movably disposed in said second chamber for interactionwith said opening so as to be responsive to diflerential fluid forcesacting on said valve means to move said valve means to a positionrestricting hydraulic fluid flow through said opening when the pistonhead moves toward said first end plate means,

and to a position permitting free flow from said accumulator meansthrough said opening when said piston head moves in the oppositedirection.

12. The device set forth in claim 11 in which the hydraulic fluidmetering means comprises passages in the wall of the cylinderestablishing progressively varying restricted communication between thetwo chambers as the piston head moves in the cylinder.

References Cited The following references, cited by the Examiner, are ofrecord in the patented file of this patent or the original patent.

UNITED STATES PATENTS 3 215,283 11/1965 Shaver 213-43 3,257,000 6/1966Cope 213-43 2,816,670 12/1957 Edwards et a1. 213--43 2,994,442 8/1961Frederick 213-43 3,033,384 5/1962 Zanow et al. 213-43 3,150,783 9/1964Campbell et a1. 213-43 3,175,699 3/1965 Price et all 213-43 3,190,4586/1965 Zanow 213-43 3,193,112 7/1965 Karakashjan et al. 213-43 3,207,3249/1965 Blake 213-8 3,232,443 2/1966 Smith 213-8 3,240,355 3/1966Karbowniczek 213-43 3,301,410 1/1967 Seay 213-43 DRAYTON E. HOFFMAN,Primary Examiner.

